Problem: Evaluate the following expression when $x = 3$ and $y = 8$. $4$ $x$ $ + 4$ $y$ $ - 4$
Answer: Substitute $3$ for ${x}$ and $8$ for ${y}$ $ = 4{(3)} + 4{(8)} - 4 $ $ = 12 + 32 - 4 $ $ = 40$